Means for handling freshly galvanized pipe during internal swabbing



Feb. 25, 1958 w. s. PEARSON 2,824,542

MEANS FoR HANDLING FRESHLY GALVANIZED PIPE DURING INTERNAL SWABBINGOriginal Filed 001;. 5, 1950 2 Sheets-Sheet 1 W M W I MY/jazzz 5. PenmanFeb. 25, 1958 w. s. PEARSON 2,824,542

MEANS FOR HANDLING FRESHLY GALVANIZED PIPE DURING INTERNAL SWABBINGOriginal Filed Oct. 5, 1950 2 Sheets-Sheet 2 WL/ [jam 5. Pearson IUnited States Patent MEANS FOR HANDLING FRESIILY GALVANIZED PIPE DURINGINTERNAL SWABBING William S. Pearson, Baltimore, Md., assignor toClifton Conduit Company, Inc., Baltimore, Md., a corporation of MarylandOriginal application October 5, 1950, Serial No. 188,622,

now Patent No. 2,753,837, dated July 10, 1956. Divided and thisapplication March 27, 1956, Serial No. 574,298

12 Claims. (Cl. 11860) The present invention relates to improvements inmeans for handling freshly galvanized pipe during internal swabbing toremove excess galvanizing metal from the internal walls of the pipe.

An important object of the present invention is to provide improvedmeans for holding an end of a freshly galvanized pipe or conduit sectionfirmly in the mouth of a blow tube while heated swabbing fluid is blowninto and through the interior of the pipe to expel excess galvanizingfluid therefrom.

Another object of the invention is to provide improved intermittentlyoperable pinch roll means adapted to operate momentarily in coordinationwith other freshly galvanized conduit handling mechanism as asupplementary supporting and driving expedient.

A further object of the invention is to provide an improved separablepipe-supporting and motivating pinch roll assembly adapted for use inapparatus for handling freshly galvanized pipe during removal of excessgalvanizing material therefrom.

Other objects, features and advantages of the present invention ,will bereadily apparent from the following detailed description of a preferredembodiment thereof taken in conjunction with the accompanying drawingsin which:

Figure 1 is a more or less schematic elevational view of an apparatusfor removing excess galvanizing material from freshly galvanized pipe orconduit, and utilizing the present invention; and

Figure 2 is a more or less schematic view on an enlarged scale takensubstantially on the line II-II of Figure 1, showing certain parts insection and others in elevation in the separable conduit-supporting andmotivating pinch roll assembly.

An apparatus for removing excess galvanizing material from freshlygalvanized pipe or conduit, as shown in Figure 1, comprises a pair ofmagnetic overhead conveyor rolls 5 supported by a framework 7 adjacentto a zinc tank or pot 8 for the galvanizing bath in which successiveconduit sections 9 are freshly galvanized and then delivered to theundersides of the conveyor rolls 5 which thereupon support the same andimpel the freshly galvanized conduit longitudinally forwardly throughrespective aligned openings in the sides of a spatter chamber 10. Meansfor driving the conveyor rolls 5 comprise a motor 11 mounted on thespatter chamber and suitably drivingly connected with the conveyor rollsthrough means such as a chain drive 12. As the hot, freshly galvanizedconduit sections emerge from the side of the spatter chamber beyond theconveyor rolls 5, the sections pass progressively through a ring swab 13from which encircling jets of heated swabbing fluid such as super-heatedsteam are impinged upon the external surface of the pipe to swab excessgalvanizing fluid from the outer surface of the conduit and drive theexcess galvanizing fluid into the spatter chamber 10.

Immediately after traveling beyond the external swab 13, the pipesection 9 is engaged between a pair of pinch ward toward andsuccessively into engagement with spaced overhead magnetic conveyorrolls 15 which, through the medium of a chain drive 17, are actuated bythe motor 11. As will be observed, the path of movement of the conduitsection 9 is a diagonally upward direction so as to facilitate theswabbing process.

After the pipe section 9 undergoing swabbing has been moved by the pinchrolls 14 and the conveyor rolls 15 to a position where only the trailingextremity portion of the pipe remains inside the spatter chamber 10, theconduit or pipe section is released from the conveyor rolls 15 bydeenergization of the rolls, and the forward end portion of the conduitsection is received in the mouth of a gooseneck blow tube 18 from whicha charge or blast of internal swabbing fluid such as superheated steamis driven into and through the interior of the pipe 9 to swab and ejectexcess galvanizing material therefrom into the spatter chamber 10.

One of the functions of the pinch rolls 14 is to maintain endwiseforward pressure on the pipe 9 while it is in the mouth of the blow tube18 and for this purpose the pinch rolls 14 are motivated by suitablechain drive from the motor 11 through the medium of a slip clutcharrangement of suitable character which will maintain the pinch rolls inoperation until predetermined resistance to forward movement of theengaged pipe 9 is encountered whereupon the slip clutch operates topermit the rolls to remain in stationary engagement with forwardpressure on the pipe.

However, it has been found that if suflicient resistance to slippage isbuilt into the slip clutch for the pinch rolls 14 to maintain adequateforward pressure on the pipe 9 to hold the forward end thereof in themouth of the blow tube 18 with suflicient firmness to avoid displacementthereof from the blow tube mouth and consequent avoidance of leakage andloss of swabbing fluid force, there is undue likelihood of slippage anddamage to the external surface of the freshly galvanized pipe where itis gripped by the pinch rolls 14.

Therefore, there is provided by the present invention additional meansfor engaging and impelling the freshly galvanized pipe 9, or at leasturging the pipe 9 into the mouth of the blow tube 18 with suflicientforce, supplemental to the force applied thereto by means of the pinchrolls 14 to assure freedom from reverse displacement of the tube fromfirm engagement within the blow tube mouth when the force of theinternal swabbing fluid is released into the pipe. Herein suchadditional means comprises an assembly 20 supported by the framework 7as near as practicable to the head of the blow tube 18 and including apair of cooperable pinch rolls 21' and 22 disposedto engage the pipesection 9 therebetween after the same has been released from theoverhead conveyor rolls 15 and for imparting to the pipe section forwardthrust supplemental to the forward thrust of the first mentioned pinchrolls 14 which engage the trailing end portion of the pipe.

In a practical form, the auxiliary thrust imparting mechanism 20comprises a roll-supporting framework in cluding an upright or standard23 for supporting the pinch roll 21 and an upright or standard 24 forsupporting thepinch roll 22 (Fig. 2). The standards 23 and 24 aresecured together by braces 20 and further secure'dby rolls 14 whichsupport and impel the conduit section on means of pivot bolts 23 and 24'respectively to angle. brackets 25 on the respective upper side portionsof the frame 7 so as to support the pinch rolls 21 and 22' onrespectively opposite sides of the path of movement ofthje pipe section9 to be swabbed. By preference the standards 23 and 24 are insulatedfrom the framework 7 by means of insulating material 27 interposedbetween the brackets 25 and the respective standards, the insulatingvmaterial being either for vibration insulation or electrical insulationor both. 7 a

Each of the pinch rolls 21 and 22 is directly carried by a respectiveelongated shaft 28 to the lower end of which the pinch roll isappropriately secured while the upper end of the shaft is supported by arocker bearing 29 mounted on a bracket 30 secured to the upper endportion of the respective standards 23 and 24. Through this arrangement,a small rocking movement in the hearing 29 affords relatively largeswinging leverage movement of the lower end portion of the respectiveroll shaft 28.

The position of one of the pinch rolls 21 or 22, in the present instanceof the pinch roll 22 is adjustably maintained in transverse relation tothe path of movement of the pipe sections 9 by means of an arm or rod 31having a bearing 32 thereon in engagement with the adjacent shaft 28 forthe roll 22 adjacent the lower end portion of the roll shaft. The outerend portion of the rod 31 is attached to the standard 24 forlongitudinal adjustment which is fixedly maintained by means such aslock nuts 33. Through this arrangement the pinch roll 22 can beaccurately adjusted transversely of the path of movement of the pipesections 9 by manipulation of the adjustment and retaining rod 31 foraccommodating various sizes of pipe. In the adjustment the shaft 28 forthe roll 22 rocks about the support provided by the bearing 29.

The whole pinch roll thrust imparting mechanism 20 is also adjustablysupported for angular adjustment about the horizontal axis of pivotbolts 23 and 24' by an adjustable turnbuckle 20a connecting threadedrods 20b and 200 that are respectively connected to the upper brace 20'and the standard 7 in the region of the blow tube 18. Tightening of theturnbuckle 20a will cause relative counterclockwise movement of thewhole thrust imparting assembly as viewed in Figure 1 while looseningthereof will cause clockwise movement of the assembly also as viewed inFigure 1. By preference the assembly is shown in a vertical or nearvertical position as pivoted about the pivot bolts 23 and 24 on theangle brackets 25.

Rotation of the pinch rolls 21 and 22 in unison is effected by meanssuch as meshing large tooth gears 34 carried by the respective shafts 28adjacent to the upper ends of the shaft close to the supporting rockerbearings 29. Hence, substantial relative adjustment in the spacingbetween the pinch rolls 21 and 22 can be effected without interferingwith the proper meshing of the gears 34 to drive the shafts 28 and thusthe pinch rolls in unison in respectively opposite direction.

Means for driving the pinch rolls comprises a motor 35 which isdrivingly connected through a gear train 37 with the drive shaft 28 ofone of the pinch rolls, herein of the pinch roll 21. Here, again, thegear connection is effected adjacent to the upper end of the shaftassembly so that minimum interference with proper meshing of thetransmission gears will occur throughout the range of relative spacingadjustment of the pinch rolls.

The arrangement and construction of the auxiliary pinch roll assembly issuch that the pinch rolls 21 and 22 remain separated sufficiently topermit free movement of the pipe section 9 to be swabbed therebetweenunder the influence of the conveyor rolls until the conveyor rolls 15are deenergized and release the conduit section. Thereupon, the pinchrolls 21 and 22 are coordinated in operation with the conveyor rolls 15so that the pinch rolls 21 and 22 enter into engagement with the pipe 9when the same has dropped slightly from the conveyor rolls 15 to theproper elevation for entering into swabbing registration within themouth of the blow tube 18. Means for accomplishing this compriseelectrically controlled pneumatic apparatus including a pneumaticoperator 38 having a cylinder 39 with a piston 40 operative thereinreciprocably and provided with a piston rod 41 appropriately connectedto a bearing structure 42 on the shaft 28 of the pinch roll 21.Rcciprocations' of the piston 40 are effected by pressure fluid suppliedfrom a suitable source through a supply duct 43 under the control of avalve 44 which is operable for alternately opening and closingappropriate passages leading from the supply duct 43 to opposite ends ofthe cylinder 39. A spring 47 normally biases the valve 44 in onedirection while a solenoid operator 45 is operative when energized tomove the valve 40 in the opposite direction in opposition to the bias ofthe spring 47. Herein the spring 47 normally acts to urge the valve 44into the reverse position from that shown in Figure 2, namely into theposition wherein pressure fluid is delivered to the forward end of thecylinder 39 so as to drive the piston 40 away from the attached shaft 28whereby the piston rod 41 draws the shaft 23 and thereby the pinch roll21 toward the left as seen in Figure 2, namely into the dot dashposition shown which is the separated condition of the pinch rolls sothat a pipe section 9 can be freely run into position therebetween. Forreversing the piston, that is for driving the piston into the positionshown in Figure 2, the solenoid 45 is actuated by closing of a switch 48in an electrical circuit 49 for supplying the solenoid with electricalenergy from a source of electrical energy from an electrical supplycircuit 50 which is also connected to the motor for supplying the motorwith electrical energy. It will be understood that the switch 48 whileshown merely symbolically in the drawing, may be connected into oroperated by any appropriate or desired means in coordination with andautomatically as an incident to operation of the machine organizationwith which the pinch roll assembly 20 is utilized. In my Patent No.2,606,846 issued August 12, 1952, which was copending with myapplication Serial No. 188,622, filed October 5, 1950, which is a parentapplication to the instant application, electrical circuits forsynchronizing and integrating operation of the machine as a whole aredisclosed in detail and the switch 48 may be readily incorporated intoone of those circuits or operating means therefor. In any event, whenthe switch 48 is closed, the solenoid operator 45 is energized andactuates the control valve 44 to drive the piston into the positionwherein the pinch roll 21 approaches the companion pinch roll 22 andthereby engages the pipe section 9 therebetween firmly but in cushionedrelation by reason of the pneumatic fluid used for driving the piston.Pneumatic fluid is superior to hydraulic fluid for this use because ofits cushioning quality whereby to compensate for any irregularities thatmay be present in the apparatus or in the engaged pipe section and thusavoid damaging the freshly coated external surface of the pipe section.

In the operation of the valve 44, exhaust from the cylinder 39 iscontrolled by an auxiliary valve section 51 on the valve 44 and whichcontrols exhaust ducts leading from the opposite ends of the cylinder 39to an exhaust outlet 52.

Swinging operations or oscillations of the pinch roll 21 as controlledby the pneumatic operator 38 are correlated with operations of theconveyor rolls 15 and of the blow tube 18 in the following fashion. Whena freshly galvanized pipe section 19 has been advanced by the pinchrolls' 14 and the conveyor rolls 15 to a position wherein the leadingend of the pipe section has just reached the point where it will engagewithin the mouth of the waiting blow tube 18, that is the position shownin full line in Figure 1, the rolls 15 are deenergized to released theconduit section which by this time, of course, has been ad vanced into aposition between the separated pinch rolls 21 and 22. Closelycoordinated with release of the conduit section from the overheadconveyor rolls 15 and thereby slight dropping down of the forward endportion thereof, the switch 48 is closed, thereby effecting energizationof the solenoid and actuation of the control valve 44 and driving of thepiston 40 to cause the shaft 28 to which connected to move laterally anddrive the pinch roll 21 into pipe gripping relationship to the companionpinch roll 22. Throughout the operation of the machine, the motor 35continues in operation to drive the pinch rolls 21 and 22 rotatably inthe direction which upon engagement of the pinch rolls 21 and 22 withthe pipe section therebetween will cause advancing movement or at leastforward thrust of the pipe section.

Since at the moment the leading end of the pipe section 9 engages inthrusting relation within the mouth of the blow tube 18, it is desirablethat the pinch rolls 21 and 22, similarly as the pinch rolls 14, ceaserotating, or at least not move relative to the engaged pipe section 9,so as to avoid marring the engaged surface of the pipe. Slip clutchmeans could be used for this purpose similarly as in connection with thepinch rolls 14, but a practical expedient utilized for this purposecomprises having the motor 35 of the three phase type so that in thepresence of predetermined resistance to turning of the motor, it

will be held immovable, but yet remain under torque, withoutoverheating. As a result, when the leading end of the pipe section comesto rest within the mouth of the blow tube 18, the pinch rolls 21 and 22cease rotating but maintain their grip on the pipe section and continueimparting forward thrust to the pipe section which supplements thethrust of the pinch rolls 14 and assures that the leading end of thepipe section remains firmly and undisplaceably in substantially sealingengagement within the blow tube mouth so that full efiiciency of theblast of internal swabbing fluid from the blow tube will result.

Promptly upon completion of the internal swabbing action, the blow tube18 is retracted into the dash line position shown in Figure 1, by actionof a fluid operated cylinder and piston actuator 53. Thereupon, thepinch rolls 14 and the pinch rolls 21 and 22 resume rotary activity andthe blown pipe section 9 is advanced to clear the trailing end portionthereof from the pinch rolls 14. In correlation with this activity, theswitch 48 is opened at the proper movement for breaking the energizingcircuit to the solenoid 45, the valve 44 reverses, causing reversal ofthe piston 40 and retraction of the pinch roll 21 for releasing theblown pipe section. The released pipe section drops down onto a conveyor54 as shown in Figure 1 and is carried on to a discharge point away fromthe machine. In the meantime, a succeeding pipe section 9 to be swabbedis advanced toward and into swabbing position and the cycle of operationresumed.

Inasmuch as chilling of the pipe sections 9 to be swabbed should beavoided, means are preferably provided for heating the pinch rolls 21and 22. For this purpose electrical heating may be resorted to, thepinch rolls being provided with internal electrical heating units 55supplied with electrical energy from a supply circuit 57' operativelyassociated with the electrical heating units 55 through the medium ofappropriate commutator assemblies 58 carried by the drive shafts 28 forthe pinch rolls.

The present application is a continuation-in-part of my copendingapplication Serial No. 188,622 filed October 5, 1950, now Patent No.2,753,837 dated July 10, 1956.

It will be understood that modifications and variations may be effectedwithout departing from the scope of the novel concepts of the presentinvention.

I claim as my invention:

' 1. In combination in apparatus for removing excess galvanizingmaterial from successive sections of freshly galvanized pipe, means forexternally swabbing the pipe sections as'they are advanced through alongitudinal path, means for advancing the pipe sections beyond saidexternal swabbing means and including an overhead magnetic conveyor, andan internal swabbing blow tube having a mouth disposed for engagement bythe leading end of each of the pipe sections after the same has beensubstantially advanced by said overhead conveyor, said overhead conveyorbeing controllable to release the pipe sections when the leading end ofeach of the sections is in proximity to the mouth of said blow tube, theimprovement which comprises means operable at longitudinally spacedpoints on the successive pipe sections to thrust the same into the mouthof the blow tube after release from said overhead conveyor. 1

2. In combination in apparatus for removing excess galvanizing materialfrom successive sections of freshly galvanized pipe, means forexternally swabbing the pipe sections as they are advanced through alongitudinal path, means for advancing the pipe sections beyond saidexternal swabbing means and including an overhead magnetic conveyor, andan internal swabbing blow tube having a mouth disposed for engagement bythe leading end of each of the pipe sections after the same has beensubstantially advanced by said overhead conveyor, said overhead conveyorbeing controllable to release the pipe sections when the leading end ofeach of the sections is in proximity to the mouth of said blow tube, theimprovement which comprises means operable at longitudinally spacedpoints on the successive pipe sections to thrust the same into the mouthof the blow tube after release from said overhead conveyor, said thrustmeans including a set of pinch rolls engageable with the trailing endportion of the successive sections and a set of pinch rolls disposed toengage the pipe sections at a more advanced point and operable to engagethe pipe sections after release of the pipe sections from the overheadconveyor.

3. In combination in apparatus for removing excess galvanizing materialfrom freshly galvanized pipe sections, a spatter chamber, said chamberhaving a passage therethrough, means for advancing a freshly galvanizedpipe section through said passage, means at the exit side of saidpassage for externally swabbing the pipe section and driving the excessgalvanizing material from the exterior of the pipe section into thespatter chamber, a set of pinch rolls immediately beyond said externalswabbing means engageable with the pipe section for advancing the samepast said external swabbing means, an overhead magnetic conveyorengageable with the pipe section beyond said pinch rolls, and aninternalswabbing blow tube having a mouth disposed to be engaged by theleading end of the pipe section after the trailing end thereof hasattained a position close to the exit of the spatter chamber but remainstherein for delivering a blast of internal swabbing fluid into the pipesection, said overhead magnetic conveyor being controllable to releasethe pipe section therefrom when the leading end of the pipe sectionreaches a position proximate said blow tube mouth, the improvement whichcomprises means operative supplementary to said pinch rolls forimparting forward thrust to the pipe section after release thereof fromsaid overhead conveyor in order to assure a firm and undisplaceableengagement of the leading end of the pipe section in said blow tubemouth when the internal swabbing blast is released thereinto.

4. In combination in apparatus for removing excess galvanizing materialfrom freshly galvanized pipe sections, a spatter chamber, said chamberhaving a passage therethrough, means for advancing a freshly galvanizedpipe section through said passage, means at the exit side of saidpassage for externally swabbing the pipe section and driving the excessgalvanizing material from the exterior of the pipe section into thespatter chamber, a set of pinch rolls immediately beyond said externalswabbing means engageable with the pipe section for advancing the samepast said external swabbing means, an overhead magnetic conveyorengageable with the pipe section beyond said pinch rolls, and aninternal swabhing blow tube having a mouth disposed to be engaged by theleading end of the pipe section after the'trailing end thereof hasattained a position close to the exit of the spatter chamber but remainstherein for delivering a blast of internal swabbing fluid into the pipesection, said overhead magnetic conveyor being controllable to releasethe pipe section therefrom when the leading end of the pipe sectionreaches a position proximate said blow tube mouth, the improvement whichcomprises means operative supplementary to said pinch rolls forimparting forward thrust to the pipe section after release thereof fromsaid overhead conveyor in order to assure a firm and undisplaceableengagement of the leading end of the pipe section in said blow tubemouth when the internal swabbing blast is released thereinto, saidsupplemental means comprising a set of pinch rolls engageable with anadvanced portion of the pipe section.

5. In combination in apparatus for removing excess galvanizing materialfrom successive sections of freshly galvanized pipe, an internalswabbing blow tube, and means for advancing a freshly galvanized pipesection into operative relation to said blow tube, the improvement whichcomprises means for gripping the pipe section to be blown atlongitudinally spaced points and thrusting the leading end of the pipesection into firm engagement with said blow tube.

6. In combination in apparatus for removing excess galvanizing materialfrom successive sections of freshly galvanized pipe, an internalswabbing blow tube, and

means for advancing a freshly galvanized pipe section into operativerelation to said blow tube, the improvement which comprises means forgripping the pipe section to be blown at longitudinally spaced pointsand thrusting the leading end of the pipe section into firm engagementwith said blow tube, said last mentioned means including separate pairsof cooperating pinch rolls,

7. In combination in a machine for removing excess galvanizing materialfrom freshly galvanized pipe sections and including an internal swabbingblow tube having a mouth into which the leading end of a pipe section isadapted to be inserted for receiving a blast of internal swabbing fluidfrom the blow tube, the improvement which comprises a pair of pinchrolls at substantial distance from the blow tube for engaging andadvancing a pipe section endwise toward the blow tube, and a second pairof pinch rolls nearer the blow tube for engaging the pipe section, bothof said pairs of pinch rolls having driving means operable to thrust thepipe section toward and into engagement with the blow tube and beingresponsive to predetermined thrust pressures to yield sufiiciently toavoid further rotation of the rolls while continuously maintainingforward thrust force on the engaged pipe section.

8. In combination in apparatus for removing fluent excess galvanizing.metal from successive sections of freshly galvanized pipe, andincluding a blow tube having a discharge end disposed for operation in afixed position, an overhead magnetic conveyor comprising conveyor rollsspaced apart and mounted to direct a freshly galvanized pipe endwisetoward engagement with said blow tube discharge end, and means forcontinuously actuating said magnetic conveyor rolls, said conveyor rollsbeing operable to drop the pipe therefrom at approximately reaching ofthe advance end of the pipe into engagement with said blow tube end, theimprovement which comprises a vertical supporting structure mountedintermediate said conveyor rolls, a pair of cylindrical periphery pinchrolls mounted on vertical shafts on said supporting structure and withthe peripheries of the pinch rolls spaced apart on respectively oppositesides of the path of movement of the pipe between said conveyor rolls,means for relatively actuating the pinch rolls to move into and out ofgripping relation to a pipe therebetween coordinated to effect grippingof a pipe when the pipe is dropped by said conveyor rolls, and means forrotating said pinch rolls to drive the pipe forwardly endwise forengagement at its leading end with said blow tube end, said lastmentioned means being responsive to thrust pressure of the end of thepipe against the end of the blow tube to yield for halting of rotationof the pinch rolls upon halting in the forward movement of the pipe soas to avoid marring the freshly galvanized external surface of the pipe.

9. In combination in a machine for removing excess galvanizing materialfrom freshly galvanized pipe sections, an internal swabbing blow tubehaving a mouth into which the leading end of a pipe section is adaptedto be inserted for receiving a blast of internal swabbing fluid from theblow tube, and a pair of pinch rolls at substantial distance from theblow tube for engaging and advancing a pipe section endwise toward theblow tube, the improvement which comprises a second pair of pinch rollsnearer the blow tube for engaging the pipe section, said pairs of pinchrolls having respective driving means operable to thrust the pipesection toward and into endwise engagement with the blow tube mouth tomaintain the end of the pipe section firmly in said month while swabbingfluid is blown into the pipe, and respective pinch roll driving meansincluding respective means responsive to predetermined thrust pressureof the pipe section into said mouth to yield sufliciently to avoidfurther rotation of the respective pairs of rolls while continuouslymaintaining forward thrust force on the engaged pipe section.

10. In combination in apparatus for removing excess galvanizing materialfrom successive sections of freshly galvanized pipe including aninternal swabbing blow tube, and means for advancing a freshlygalvanized pipe section into operative relation with said blow tube, theimprovement which includes part of said advancing means and additionalmeans cooperative therewith for gripping the pipe section to be blown atlongitudinally spaced points and thrusting the leading end of the pipesection into firm engagement with the blow tube.

11. In combination in apparatus for removing excess galvanizing materialfrom successive sections of freshly galvanized pipe including aninternal swabbing blowing tube, and means for advancing freshlygalvanized pipe section into operative relation with said blown tube,the improvement which comprises separate pairs of pinch rolls forgripping the pipe section to be blown at longitudinally spaced pointsand thrusting the leading end of the pipe section into firm engagementwith said blow tube, at least one of said pairs of pinch rolls beingseparable for releasing and gripping the pipe section.

12. In combination in apparatus for removing excess galvanizing materialfrom successive sections of freshly galvanized pipe including anexternal swabbing ring arranged for passage of the pipe sectiontherethrough, an internal swabbing blowing tube, and means for advancingfreshly galvanized pipe section into operative relation with said blowtube, the improvement which comprises separate pairs of pinch rolls forgripping the pipe section to be blown at longitudinally spaced pointsand thrusting the leading end of the pipe section into firm engagementwith said blow tube, at least one of said pairs of pinch rolls beingseparable for releasing and gripping the pipe section,

References Cited in the file of this patent UNITED STATES PATENTS2,606,846 Pearson Aug. 12, 1952

